This invention relates to an articulated pad for disc brakes comprising at least two pieces which are hinged together.
Pads for disc brakes comprising several independent parts which are distributed circumferentially about the periphery of the brake disk, adjacent to each other, are known. In comparison with monoblock pads, these pads have the advantage that they ensure more uniform wear and a longer service life, despite a reduction in braking efficiency.
Nevertheless, these pads have some disadvantages in that once they have been fitted to the brake shoes the pads are interlocked with each other by curvilinear sections joined by their adjacent sides, and these consist of separate parts before assembly, that is it makes them difficult to fit, and it is first of all necessary to have the various parts in their correct relative positions and then insert them together into the appropriate housing in the brake shoe, where they are retained by a securing plate.
A further disadvantage in comparison with monoblock pads lies in the greater overall play resulting from machining tolerances relative to the dimensions of the housing.
Because braking operations are intermittent and the relative position of the parts can be considered random before any braking action, although within the limits of the permitted play, during the course of braking the forces acting tend to force the parts to adopt a predetermined relative contact position with the matched curvilinear sections, causing appreciable wear of the matching profiles in areas of relatively large slip, with an increase in play which results in relative radial displacement between these parts with reference to the axis of rotation of the disc.
This gives rise to greater wear of the pad friction material in the radially peripheral strips, with some reduction in braking efficiency, appreciable noise and, ultimately, a reduction in the operating safety of the braking system.
The problem underlying this invention is that of devising an articulated pad for disc brakes which has structural and functional characteristics which will overcome the abovementioned disadvantages in comparison with the articulated pads in the known art.
This problem is overcome by an articulated pad for disc brakes in accordance with the present invention.
This invention overcomes these problems and offers articulated pads in a plurality of parts, preferably but not necessarily two, articulated together with a hinge link which permits a certain amount of relative movement by the parts in the direction of the axis of the hinge, perpendicular to the plane of the disc brake, while permanently attaching them to each other so that installation is made very much easier.
In addition to this the hinge link limits the possibilities for radial displacement of the two parts in relation to the axis of the disc, permitting a certain amount of relative movement between the parts in the plane of the disc in a direction perpendicular to the radial direction so that the matching surfaces of the two adjacent parts can come into contact, although with play, and discharge the stresses induced by braking from one to the other without causing significant relative sliding between the stressed parts, with consequent wear, and without the links being subjected to significant stresses.